The Trump Boom Is No Mere ‘Sugar High’

The tax cuts primed the productive economy for long-term growth, not a short-term buzz.

Liberals are tripping over themselves to explain why the economy has performed so much better under Donald Trump than it did under Barack Obama. The economy has grown by nearly 4% over the past six months, and the final number for 2018 is expected to come in at between 3% and 3.5%. The U.S. growth rate has doubled since Mr. Obama’s last year in office.

When Mr. Trump was elected, many Democratic pundits predicted an economic and stock-market meltdown. Then the economy started surging and they abruptly changed their tune, arguing...